Hi Viet,
we have FreeRTOS integrated in our SDK for S32K devices. If customers want to use another OS, it must be ported by themselves. Please check the website of Threadx - porting guides are usually provided. Here is an example of porting guide for FreeRTOS: https://www.freertos.org/FreeRTOS-porting-guide.html
If the Threadx is compatible with Cortex M4, it will be compatible also with S32K148.
Regards,
Lukas